Module CCString

Basic String Utils

type 'a gen = unit -> 'a option
type 'a sequence = ('a -> unit) -> unit
type 'a klist = unit -> [ `Nil | `Cons of 'a * 'a klist ]

Common Signature

module type S = sig ... end

Strings

include module type of sig ... end
val length : string -> int
val get : string -> int -> char
val set : bytes -> int -> char -> unit
val create : int -> bytes
val make : int -> char -> string
val init : int -> (int -> char) -> string
val copy : string -> string
val sub : string -> int -> int -> string
val fill : bytes -> int -> int -> char -> unit
val blit : string -> int -> bytes -> int -> int -> unit
val concat : string -> string list -> string
val iter : (char -> unit) -> string -> unit
val iteri : (int -> char -> unit) -> string -> unit
val map : (char -> char) -> string -> string
val mapi : (int -> char -> char) -> string -> string
val trim : string -> string
val escaped : string -> string
val index : string -> char -> int
val index_opt : string -> char -> int option
val rindex : string -> char -> int
val rindex_opt : string -> char -> int option
val index_from : string -> int -> char -> int
val index_from_opt : string -> int -> char -> int option
val rindex_from : string -> int -> char -> int
val rindex_from_opt : string -> int -> char -> int option
val contains : string -> char -> bool
val contains_from : string -> int -> char -> bool
val rcontains_from : string -> int -> char -> bool
val uppercase : string -> string
val lowercase : string -> string
val capitalize : string -> string
val uncapitalize : string -> string
val uppercase_ascii : string -> string
val lowercase_ascii : string -> string
val capitalize_ascii : string -> string
val uncapitalize_ascii : string -> string
type t = string
val compare : t -> t -> int
val equal : t -> t -> bool
val split_on_char : char -> string -> string list
val to_seq : t -> char Stdlib.Seq.t
val to_seqi : t -> (int * char) Stdlib.Seq.t
val of_seq : char Stdlib.Seq.t -> t
val unsafe_get : string -> int -> char
val unsafe_set : bytes -> int -> char -> unit
val unsafe_blit : string -> int -> bytes -> int -> int -> unit
val unsafe_fill : bytes -> int -> int -> char -> unit
val equal : string -> string -> bool

Equality function on strings.

val compare : string -> string -> int
val is_empty : string -> bool

is_empty s returns true iff s is empty (i.e. its length is 0).

since
1.5
val hash : string -> int
val init : int -> (int -> char) -> string

Like Array.init.

since
0.3.3
val rev : string -> string

rev s returns the reverse of s.

since
0.17
val pad : ?⁠side:[ `Left | `Right ] -> ?⁠c:char -> int -> string -> string

pad n str ensures that str is at least n bytes long, and pads it on the side with c if it's not the case.

parameter side

determines where padding occurs (default: `Left).

parameter c

the char used to pad (default: ' ').

since
0.17
val of_char : char -> string

of_char 'a' is "a".

since
0.19
val of_gen : char gen -> string

Convert a gen of characters to a string.

val of_seq : char sequence -> string

Convert a sequence of characters to a string.

val of_klist : char klist -> string

Convert a klist of characters to a string.

val of_list : char list -> string

Convert a list of characters to a string.

val of_array : char array -> string

Convert an array of characters to a string.

val to_array : string -> char array

Return the array of characters contained in the string.

val find : ?⁠start:int -> sub:string -> string -> int

Find sub in string, returns its first index or -1.

val find_all : ?⁠start:int -> sub:string -> string -> int gen

find_all ~sub s finds all occurrences of sub in s, even overlapping instances.

parameter start

starting position in s.

since
0.17
val find_all_l : ?⁠start:int -> sub:string -> string -> int list

find_all_l ~sub s finds all occurrences of sub in s and returns them in a list.

parameter start

starting position in s.

since
0.17
val mem : ?⁠start:int -> sub:string -> string -> bool

mem ~sub s is true iff sub is a substring of s.

since
0.12
val rfind : sub:string -> string -> int

Find sub in string from the right, returns its first index or -1. Should only be used with very small sub.

since
0.12
val replace : ?⁠which:[ `Left | `Right | `All ] -> sub:string -> by:string -> string -> string

replace ~sub ~by s replaces some occurrences of sub by by in s.

parameter which

decides whether the occurrences to replace are:

  • `Left first occurrence from the left (beginning).
  • `Right first occurrence from the right (end).
  • `All all occurrences (default).
raises Invalid_argument

if sub = "".

since
0.14
val is_sub : sub:string -> int -> string -> int -> sub_len:int -> bool

is_sub ~sub i s j ~len returns true iff the substring of sub starting at position i and of length len is a substring of s starting at position j.

val repeat : string -> int -> string

The same string, repeated n times.

val prefix : pre:string -> string -> bool

prefix ~pre s returns true iff pre is a prefix of s.

val suffix : suf:string -> string -> bool

suffix ~suf s returns true iff suf is a suffix of s.

since
0.7
val chop_prefix : pre:string -> string -> string option

chop_prefix ~pre s removes pre from s if pre really is a prefix of s, returns None otherwise.

since
0.17
val chop_suffix : suf:string -> string -> string option

chop_suffix ~suf s removes suf from s if suf really is a suffix of s, returns None otherwise.

since
0.17
val take : int -> string -> string

take n s keeps only the n first chars of s.

since
0.17
val drop : int -> string -> string

drop n s removes the n first chars of s.

since
0.17
val take_drop : int -> string -> string * string

take_drop n s = take n s, drop n s.

since
0.17
val lines : string -> string list

lines s returns a list of the lines of s (splits along '\n').

since
0.10
val lines_gen : string -> string gen

lines_gen s returns a generator of the lines of s (splits along '\n').

since
0.10
val concat_gen : sep:string -> string gen -> string

concat_gen ~sep g concatenates all strings of g, separated with sep.

since
0.10
val unlines : string list -> string

unlines l concatenates all strings of l, separated with '\n'.

since
0.10
val unlines_gen : string gen -> string

unlines_gen g concatenates all strings of g, separated with '\n'.

since
0.10
val set : string -> int -> char -> string

set s i c creates a new string which is a copy of s, except for index i, which becomes c.

raises Invalid_argument

if i is an invalid index.

since
0.12
val iter : (char -> unit) -> string -> unit

Alias to String.iter.

since
0.12
val iteri : (int -> char -> unit) -> string -> unit

Iter on chars with their index.

since
0.12
val map : (char -> char) -> string -> string

Map chars.

since
0.12
val mapi : (int -> char -> char) -> string -> string

Map chars with their index.

since
0.12
val filter_map : (char -> char option) -> string -> string

filter_map f s calls (f a0) (f a1) ... (f an) where a0 ... an are the characters of s. It returns the string of characters ci such as f ai = Some ci (when f returns None, the corresponding element of s is discarded).

since
0.17
val filter : (char -> bool) -> string -> string

filter f s discards characters not satisfying f.

since
0.17
val flat_map : ?⁠sep:string -> (char -> string) -> string -> string

Map each chars to a string, then concatenates them all.

parameter sep

optional separator between each generated string.

since
0.12
val for_all : (char -> bool) -> string -> bool

True for all chars?

since
0.12
val exists : (char -> bool) -> string -> bool

True for some char?

since
0.12
include S with type S.t := string
type t
val length : t -> int

Return the length (number of characters) of the given string.

val blit : t -> int -> Stdlib.Bytes.t -> int -> int -> unit

Like String.blit. Compatible with the -safe-string option.

raises Invalid_argument

if indices are not valid.

val fold : ('a -> char -> 'a) -> 'a -> t -> 'a

Fold on chars by increasing index.

since
0.7

Conversions

val to_gen : t -> char gen

Return the gen of characters contained in the string.

val to_seq : t -> char sequence

Return the sequence of characters contained in the string.

val to_klist : t -> char klist

Return the klist of characters contained in the string.

val to_list : t -> char list

Return the list of characters contained in the string.

val pp_buf : Stdlib.Buffer.t -> t -> unit

Renamed from pp since 2.0.

val pp : Stdlib.Format.formatter -> t -> unit

Print the string within quotes.

Renamed from print since 2.0.

val drop_while : (char -> bool) -> t -> t

drop_while f s discards any characters starting from the left, up to the first character c not satisfying f c.

since
2.2
val rdrop_while : (char -> bool) -> t -> t

rdrop_while f s discards any characters starting from the right, up to the first character c not satisfying f c.

since
2.2
val ltrim : t -> t

Trim space on the left (see String.trim for more details).

since
1.2
val rtrim : t -> t

Trim space on the right (see String.trim for more details).

since
1.2

Operations on 2 strings

val map2 : (char -> char -> char) -> string -> string -> string

Map pairs of chars.

raises Invalid_argument

if the strings have not the same length.

since
0.12
val iter2 : (char -> char -> unit) -> string -> string -> unit

Iterate on pairs of chars.

raises Invalid_argument

if the strings have not the same length.

since
0.12
val iteri2 : (int -> char -> char -> unit) -> string -> string -> unit

Iterate on pairs of chars with their index.

raises Invalid_argument

if the strings have not the same length.

since
0.12
val fold2 : ('a -> char -> char -> 'a) -> 'a -> string -> string -> 'a

Fold on pairs of chars.

raises Invalid_argument

if the strings have not the same length.

since
0.12
val for_all2 : (char -> char -> bool) -> string -> string -> bool

All pairs of chars respect the predicate?

raises Invalid_argument

if the strings have not the same length.

since
0.12
val exists2 : (char -> char -> bool) -> string -> string -> bool

Exists a pair of chars?

raises Invalid_argument

if the strings have not the same length.

since
0.12

Ascii functions

Those functions are deprecated in String since 4.03, so we provide a stable alias for them even in older versions.

val capitalize_ascii : string -> string

See String.

since
0.18
val uncapitalize_ascii : string -> string

See String.

since
0.18
val uppercase_ascii : string -> string

See String.

since
0.18
val lowercase_ascii : string -> string

See String.

since
0.18
val equal_caseless : string -> string -> bool

Comparison without respect to ascii lowercase.

since
1.2

Finding

A relatively efficient algorithm for finding sub-strings.

since
1.0
module Find : sig ... end

Splitting

module Split : sig ... end
val split_on_char : char -> string -> string list

Split the string along the given char.

since
1.2
val split : by:string -> string -> string list

Alias to Split.list_cpy.

since
1.2

Utils

val compare_versions : string -> string -> int

compare_versions a b compares version strings a and b, considering that numbers are above text.

since
0.13
val compare_natural : string -> string -> int

Natural Sort Order, comparing chunks of digits as natural numbers. https://en.wikipedia.org/wiki/Natural_sort_order

since
1.3
val edit_distance : string -> string -> int

Edition distance between two strings. This satisfies the classical distance axioms: it is always positive, symmetric, and satisfies the formula distance a b + distance b c >= distance a c.

Slices

A contiguous part of a string

module Sub : sig ... end